From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 3269D6B0038 for ; Mon, 15 May 2017 04:03:29 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id q125so105482178pgq.8 for ; Mon, 15 May 2017 01:03:29 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id o6si5445882pfk.340.2017.05.15.01.03.27 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 15 May 2017 01:03:28 -0700 (PDT) Date: Mon, 15 May 2017 10:03:24 +0200 From: Michal Hocko Subject: Re: mm: page allocation failures in swap_duplicate -> add_swap_count_continuation Message-ID: <20170515080323.GD6056@dhcp22.suse.cz> References: <772d81b0-df36-8644-41ca-dc13d0c0f2b5@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <772d81b0-df36-8644-41ca-dc13d0c0f2b5@de.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Christian Borntraeger Cc: linux-mm@kvack.org, Linux Kernel Mailing List On Fri 12-05-17 11:18:42, Christian Borntraeger wrote: > Folks, > > recently I have seen page allocation failures during > paging in the paging code: > e.g. > > May 05 21:36:53 kernel: Call Trace: > May 05 21:36:53 kernel: ([<0000000000112f62>] show_trace+0x62/0x78) > May 05 21:36:53 kernel: [<0000000000113050>] show_stack+0x68/0xe0 > May 05 21:36:53 kernel: [<00000000004fb97e>] dump_stack+0x7e/0xb0 > May 05 21:36:53 kernel: [<0000000000299262>] warn_alloc+0xf2/0x190 > May 05 21:36:53 kernel: [<000000000029a25a>] __alloc_pages_nodemask+0xeda/0xfe0 > May 05 21:36:53 kernel: [<00000000002fa570>] alloc_pages_current+0xb8/0x170 > May 05 21:36:53 kernel: [<00000000002f03fc>] add_swap_count_continuation+0x3c/0x280 > May 05 21:36:53 kernel: [<00000000002f068c>] swap_duplicate+0x4c/0x80 > May 05 21:36:53 kernel: [<00000000002dfbfa>] try_to_unmap_one+0x372/0x578 > May 05 21:36:53 kernel: [<000000000030131a>] rmap_walk_ksm+0x14a/0x1d8 > May 05 21:36:53 kernel: [<00000000002e0d60>] try_to_unmap+0x140/0x170 > May 05 21:36:53 kernel: [<00000000002abc9c>] shrink_page_list+0x944/0xad8 > May 05 21:36:53 kernel: [<00000000002ac720>] shrink_inactive_list+0x1e0/0x5b8 > May 05 21:36:53 kernel: [<00000000002ad642>] shrink_node_memcg+0x5e2/0x800 > May 05 21:36:53 kernel: [<00000000002ad954>] shrink_node+0xf4/0x360 > May 05 21:36:53 kernel: [<00000000002aeb00>] kswapd+0x330/0x810 > May 05 21:36:53 kernel: [<0000000000189f14>] kthread+0x144/0x168 > May 05 21:36:53 kernel: [<00000000008011ea>] kernel_thread_starter+0x6/0xc > May 05 21:36:53 kernel: [<00000000008011e4>] kernel_thread_starter+0x0/0xc > > This seems to be new in 4.11 but the relevant code did not seem to have > changed. > > Something like this > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 1781308..b2dd53e 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -3039,7 +3039,7 @@ int swap_duplicate(swp_entry_t entry) > int err = 0; > > while (!err && __swap_duplicate(entry, 1) == -ENOMEM) > - err = add_swap_count_continuation(entry, GFP_ATOMIC); > + err = add_swap_count_continuation(entry, GFP_ATOMIC | __GFP_NOWARN); > return err; > } > > > seems not appropriate, because this code does not know if the caller can > handle returned errors. > > Would something like the following (white space damaged cut'n'paste be ok? > (the try_to_unmap_one change looks fine, not sure if copy_one_pte does the > right thing) No, it won't. If you want to silent the warning then explain _why_ it is a good approach. It is not immediatelly clear to me. > > diff --git a/mm/memory.c b/mm/memory.c > index 235ba51..3ae6f33 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -898,7 +898,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, > swp_entry_t entry = pte_to_swp_entry(pte); > > if (likely(!non_swap_entry(entry))) { > - if (swap_duplicate(entry) < 0) > + if (swap_duplicate(entry, __GFP_NOWARN) < 0) > return entry.val; Moreover if you add a gfp_mask argument then the _full_ mask should be given rather than just one of the modifiers. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org